<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>Demo</title>
</head>
<body>
<a href="http://jquery.com/">jQuery</a>
<input type="checkbox" class="participant_ajax">
<script src="jquery.js"></script>
<script>
$( document ).ready(function() {
  $( "input" ).click(function( event ) {
    //alert( "Thanks for visiting!" );
    console.log('link clicked')
    $.post('/participant/change/', 
    {
      category_id: 1
    },
    function(status){
      console.log('callback run')
      alert("Status: " + status);
    });
  });
});
</script>
</body>
</html>